NTSB calls for inspection of Boeing 737 jetliners

National Transportation Safety Board Chairman Deborah Hersman points out on a model Southwest Airlines plane the position where the fuselage skin was torn from a Boeing 737-300 aircraft during a news briefing April 5, at the NTSB headquarters in Washington, DC. The 15-year-old Southwest aircraft was on its way from Phoenix to Sacramento and had to make an emergency landing when the accident happened on Friday, April 1, 2011.

AP: The order is aimed at finding weaknesses in the metal exterior, but virtually all of the affected aircraft will have already been inspected by the time the order takes effect.

The safety directive applies to about 175 aircraft worldwide, including 80 planes registered in the U.S., the Federal Aviation Administration said. Of those 80, nearly all are operated by Southwest. Two belong to Alaska Airlines. Read the full story here.

Shawn Thew / EPA

Photographers surround the damaged fuselage skin section from Southwest Airlines Flight 812 Boeing 737 in the materials labratory at NTSB Headquarters in Washington, DC April 5. Cracks have been found in five Southwest planes after an emergency inspection was carried out on the airline's fleet when a five-foot hole 'exploded' in the roof of Flight 812 on April 1.

Go behind the scenes at the Boeing 737 factory in Renton, WA in this slideshow.

While most manufacturing is done overseas, the 737 is still made in Washington. Find out why.